标题: | 多晶锗元件的研制与分析 Fabrication and Characterization of Poly-Ge Based Devices |
作者: | 张佑宁 Chang, Yu-Ning 林鸿志 黄调元 Lin, Horng-Chih Huang, Tiao-Yuan 电子研究所 |
关键字: | 多晶锗;固相结晶法;金属诱发结晶;金属诱发掺杂活化;金属锗化物;poly-Ge;SPC;MIC;MIDA;germanides |
公开日期: | 2008 |
摘要: | 在本论文研究中,我们探讨了多晶锗薄膜和锗化镍的材料特性。藉由不同形式的结晶方法,由超高真空溅镀系统沈积的非晶锗会被转变成多晶锗薄膜。从固相结晶法(SPC)的结果,我们发现在经过500 ℃ 1小时的退火处理后,非晶锗会转变成多晶锗且晶粒尺寸会达到饱和,不再随退火时间的增加而增加尺寸。与SPC相比,金属诱发结晶法(MIC)在镍的帮助下可降低结晶温度且获得较大的晶粒尺寸。而MIC除了可以增加薄膜的结晶性之外,亦可运用于掺杂的活化,也就是金属诱发掺杂活化(MIDA)技术。因为在MIC过程中,掺杂会因晶格重排而进入取代位,所以MIDA可在低温下进行掺杂的活化。金属锗化物的使用被认为可以降低寄生电阻并解决较低的掺杂固态溶解度的问题,而我们发现形成锗化镍的适合温度为300 ℃到375 ℃。此外,在本论文中,我们也制作了五种元件,从电性结果来看,我们发现多晶矽的存在可以增加多晶锗薄膜的结晶性,而且当多晶矽是被沈积在源极和汲极端的多晶锗薄膜的下方时,多晶矽对电性的影响是最明显的。 In this study, material properties of poly-Ge thin films and Ni germanides were investigated. The poly-Ge thin films were formed by different crystallization schemes performed on a-Ge deposited by an ultra-high vacuum sputter. From the results of solid-phase crystallization (SPC) method, we found that a-Ge is transformed into poly-Ge at 500 ℃ for 1 hour annealing and then the grain size saturates. For metal-induced crystallization (MIC) method, the crystallization temperature can be reduced with the assistance of Ni and the grain size is bigger than that formed by SPC method. In addition to enhanced crystallization, MIC can be applied to activate dopants at low temperature, termed metal-induced dopant activation (MIDA), because dopants will be rearranged into the substitutional sites during MIC process. Germanide process is expected to reduce the parasitic resistance and alleviate the issue of low dopant solid solubility. We found that the suitable temperature to form NiGe is from 300 ℃ to 375 ℃. Besides, we also fabricate five types of devices in this thesis. From the electrical characteristics, we discovered that poly-Si can increase the crystallinity of poly-Ge and this apparent effect occurs when poly-Si is deposited under the poly-Ge film at the S/D region. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079611518 http://hdl.handle.net/11536/41653 |
显示于类别: | Thesis |
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